Hollow fin heat exchanger



Sept. 18, 1945. s. E. HEYMANN HOLLOW FIN HEAT EXCHANGER Filed Sept. 5. 1942 Patented Sept. 18, 1945 gsssnac io brie 3913110 eri GEKII- -aiiniicatiogewher sfisgsgggmsisemr intestinal Dammit magmas rswneasismmesei lnnn s wediimheatens .icr

at a. uniform temperature. Another obiect of my invention is to provide a new and improved holiowfln heat exchanger in which the flow oi the hot gases through the hollow fins is greater adjacent the tips of these fins than bases thereof and wherein the flow air between the hollow fins is greater adjacent the bases of the fins than adjacent the tips thereof.

Another object o! my invention is to provide a lightweight heat exchanger which is more rigid and free from vibration than the heat exchangers or the prior art.

the'flns are maintained ino nvnsnnnset sen39 aircraft piings between a or the muile I w I it t) L 5 d flelmst nh w sjimhs a s im ni bsseihella 11 smh dt emnieda se w mf a eth lsihra erimss tennemem v i. and no gases or combustion iiqg dgggg lm bLeintteirior of hesepiiollow fins and WL-peat- 'ngi 5' a, c h sea I 2 ,located between thesi ?)E r fl ii uch 'I ;Vf7 alien e heaters, the flow 0! thehot gases oi combustion is Fla. 3 is a partial end v at a maximum through the wider part 01 the iin 15 changer and is taken on the adjacent the base thereoi and at a i and thmugh the narrow part .02 the an adjacent the Fig. 4 is a partial. sectional view of the heat tip thereof, whereas the flow ct veil. atlas anis exchanger taken on the line 1-4 0! Figs-3. at a maximum adjacent the tiger fin and a In Fig; 1, I have ill ated my invention as minimum adjacent the base or the with the vm being embodied in 'a. heater which is supplied result that the tips of the flns'are relatively cool with hot gases ct combustion 'from' n,-

it while the bases of the fins are extremely hot. which may he ei a combustion chamber es- The unequal heating of the fins reduces the e spr ded f h er r which mav a transfer of heat from the hot gases to the ventibe the interior o1 hijie communicating with the, latin; air and sets up stresses in the heat ex- 5 exhaust maniielci ni aininternalcombmtien enchanger, with resulting distortion I d fatigue 0! K m 0! h 'ij fiwfi fseflr i. 11911 ei hot the metaL. Such heaters are designed for use in The hot gems peeamrn'the spacesitthrhn'gha aircraft and the metal oi which the heat exflari g annular-"inlet l2 into the -=1-.-: ,H changer is formed is made of minimum thickness with! the holiow flnvlizoi-mir new beatento reduce weight and increase efllciency'by re- 3 c --i-At. These saeesflqw lensthwlse'oi the ducing the length of the metallic path of travel passages rand-give up. thei rheet to the heat-exfor the heat transierredirom the hot gases in cha 1'11 and are then discharged iptoan outall. Under some conditions, the sidesot the hollet ch30 exlifl ti t low fins tend to produce a drumming noise when flttin: 12 illustrated as pmvided \eitlntmfldszi subjected to particular periodic vibrations. 5 toinciiitatethe attachment thetethib mealt- An object of m invention is to provide a new able-exhaust P p i and improved hollow iin heat exchanger which A mulier'fi isioeeiiilllfimthe heat WW I avoids these disadvantages of the prior art and i and ha a shed memlsheil fil ghieh islniled which is more emcient. more quiet, and tree from a heat resisting. scund ahsorhiiigmeterid 30, internal stre ses. V 40 such. 101' example. as glass wccl gnstdinless steel Mother object of my invention is to provide I. wool. The shell 18 is prqM -'Wh:a.nlura1ity of hollow fin heat exchanger in which all parts or small openings 32 which mastic-couthe We th int m r shell petmittsmmd vibrations contained in the hot-cases .tp pass into the glass wool and be -ahsorhed-therehy' v Ventilating air {In beheated is supplied to the heater throughthe' inlet en .34 of a casin'g 36- which surrounds the heat exchenger: 'i'i and cooperates therewith tov iorm sir passages 38 he tween the has it. The outlet' end 40 of the cusingjt may com unlcate either. directly with the interior oithe aircraft cabin or other space to be heated or'may ciscmg 'the heated air ha a. series of ventilating ductswhlch distribute this 48, to form the combletedheat exchang was then bent. into overlanpingfedges weldedtogether, as indicated at such a construction duced and the eiliciency is increased by reducing the metallic path of travel oi the heat.

In Fig. 2, the fins "are illustrated as having l the outlet end of the heater.

1 transmission air lengthwise of said radii shorter or longer than the radii of the curves forming the bases of these fins.

In the detailed views of Figs. 3 and 4, I have illustrated a preferred construction for closing the ends of the hollow fins. This construction includes a ring 48 located at each end of the tins and having radially projecting fingers III which with projecting flanges 52, which extend into the hollow fins and are adapted to be attached thereto by seam welding or in any other suitable mannet. The rings II also ha My novel heat exchanger is not limited to the of heat from burned cases to ventilating air, but may be utilized to transfer heat between any other fluids and is capable of zenerai to be construed as including modifications falling within the scope oi the or p nded claims.

I claim:

7 the class tubular lnember o1 eho'utits enzth rality oi hollow fins constructed i'orm described, uniform cross sai means for directing hot gases through and lensinwise or vsaid hollow fins, and meana for directing passases.

2. A heat exchangeno! the class comprising a tubular structure having longitudinally extending hollow fins projecting radially outward therefrom, said fins forming external 4. A heat exchanger. comprising a tubular longitudinally extending thin and havin: a Flu-t tips cr me fins,

described,

single-layer hollow fins projecting outwardly thereirom, said fins having interiors communicating throughout their length with the interior oi said tubular structure, said tins being wider in cross section adjacent their tips than adjacent their bases, causing the gas flowing in the inside of the this to have greater velocity adjacent the tips. and said iins iorming between them longitudinally unobstructed passages which are narrower adjacent the tips oi! said flns than adjacent their bases, causing the gas flowing on the outside of the fins to have a greater velocity adlaeent the bases, means for directing hot products of combustion into said tubular structure and lengthwise 0! said hollow tins, and means for diresting air lengthwise of said assages.

5. A light weight heat exchanger of high efliciency and adapted for operation at maximum heat output, said heat exchanger comprising a tubular structure formed oi a single layer or thin sheet metal having longitudinally extending hollow tins projecting outwardly therefrom, said fins having interiors in open communication with the interior or said tubular structure throughout th length of said fins; said tins forming external es therebetween which are open to axial flow throughout the length '0! the heat exchanger, said fins and passageslbeing 01 substantially uniform cross section throughout the length of the heatexchanger, said fins being wider at points adjacent their tips than at points adjacent their bases whereby fluid flowing inside the hollow line has a greater velocity adjacent said tips, means ior directing a hot fluid into said tubular structure and lengthwise at said hollow fins, and means for directing a relatlvely'cold fluid lengthwise of said external comprising a tubular member having a plurality of hollow iins exte her, said tins having rounded tips and bases and reversely rounded sides, said fins being wider adiacent their tips than adjacent their bases, means through said fins and lengthwise thereof, said fins being spaced to provide gas passages therebetween, and means for directing fluid lengt wise of said passages.

SEYMOUR E. HEYMANN 

